Vehicles start to be more dangerous with last vehicle perk adding secondary weapons - mg for tank, tow missile ( Its not a missile its a rocket !

) for light tanks and attack helis.
They are nowhere near the level of "I am fucked" as they are in Battlefield 2 however.
Although my biggest beef with BF2 was the damned Jetfighter pilots who just absolutely rape everything. AA emplacements were useless because the jets are so damned fast and get flares, they will kill you before you get a chance to shoot at them proper. Hell I doubt the rockets can even keep up with them properly. The only weapon that seemed to work against jets were the mobile AA's because the gun turrets on it would rip them apart in a second.
Bad Company 2, has got attack helicopters, but RPG infantry is lethal (I love the Carl Gustav) and the gun emplacements can make their life hard as well. The copters are powerfull, but have to be carefull not to get an RPG up their arse. The ground vehicles are fun as well, the bradley is a monster if its filled because RPG infantry will have to be at the rear to not get shot at from the side ports. The vehicles are just way more balanced.